1. Field of the Invention
The present invention relates to an improved vertical form, fill and seal packaging machine. More specifically, the present invention relates to a vertical food packaging machine that forms a vacuum seal of the packaged food products.
2. Prior Art
It is often desirable to seal packaged food products under a vacuum. This is typically accomplished by sucking the air out of a package prior to it being sealed. Those skilled in the art will appreciate that this is generally time consuming and therefore slows packaging process significantly.
It is therefore desirable to provide a method for rapid, sterile vacuum sealing of packaged food items.
The present invention relates to apparati and methods for making air tight bags or packages for use with a multiple purpose convertible vertical form, fill and seal machine and method for making a variety of styles or types of bags including overlap or fin seals, pillow, potato chip, non-reclosable or reclosable, product-filled bags and especially zipper lock reclosable bags.
Package or bag making machines generally referred to as vertical form, fill and seal machines and methods for manufacturing individual pillow type packages with non-reclosable, midline overlap longitudinal seams or seals are described, for example, U.S. Pat. No. 4,532,753 to Kovacs, granted Aug. 6, 1985 (U.S. Cl. 53/451); U.S. Pat. No. 4,768,327 to Mosher, granted Sep. 6, 1988 (U.S. Cl. 53/451); U.S. Pat. No. 4,965,986 to Klinkel, granted Oct. 30, 1990 (U.S. Cl. 53/551); U.S. Pat. No. 4,999,974 to Kovacs, et al., granted Mar. 19, 1991 (U.S. Cl. 53/434); and U.S. Pat. No. 5,279,098 to Fukuda, granted Jan. 18, 1994 (U.S. Cl. 53/451). Typically, a heat sealable web material is supplied from a roll and is guided to a former located at the upper end of the machine. The former folds the flat web material into a vertically oriented tube surrounding a tubular filling mandrel or pipe. The edges of the folded web material overlap one another, and, as the folded tube moves downwardly over the mandrel, the overlapped marginal edge portions are heat sealed to one another by a cyclicly operated longitudinal sealing mechanism. The web is thus formed into a web tube which is advanced through the machine in package length
Attempts have been made to provide a vertical form; fill and seal machine which produces more than one type of package.
Various zippered and zipper lock packages are seen in the following patents: U.S. Pat. No. 6,059,456, “Reclosable Profile Arrangement Using Slidable Closure Strip”, U.S. Pat. No. 5,924,173, “End Posts For Plastic Zipper”, U.S. Pat. No. 5,896,627, “High-strength Slide R For a Reclosable Bag”, U.S. Pat. No. 5,833,791, “Conforming End Stops For a Plastic Zipper”, U.S. Pat. No. 5,775,812, “Tamper-Evident Reclosable Plastic Bag With Breakaway Slide R”, U.S. Pat. No. 5,713,669, “Plastic Bag With Zipper Slide R Captured in Pocket”, and U.S. Pat. No. 5,669,715, “Tamper-Evident Reclosable Plastic Bag With Slide R”, the teachings of which are expressly incorporated by reference herein.